package com.hmdp.service.impl;

import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.SystemConstants;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;

import java.util.*;
import java.util.concurrent.TimeUnit;

import static com.hmdp.utils.RedisConstants.*;

/**
 * <p>
 * 服务实现类
 * </p>
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private CacheClient cacheClient;

    @Override
    public Result queryById(Long id) {
        //缓存穿透
//        Shop shop = cacheClient.queryWithPassThrough(CACHE_SHOP_KEY,id,Shop.class,id2->getById(id2),CACHE_SHOP_TTL,TimeUnit.MINUTES);
        Shop shop = cacheClient.queryWithPassThrough(CACHE_SHOP_KEY, id, Shop.class, this::getById, CACHE_SHOP_TTL, TimeUnit.MINUTES);
//        //互斥锁解决缓存击穿
//        Shop shop = queryWithMutex(id);

//        //逻辑过期解决缓存击穿
//        Shop shop=cacheClient
//                .queryWithLogicalExpire(CACHE_SHOP_KEY,id, Shop.class,this::getById,CACHE_SHOP_TTL,TimeUnit.MINUTES);
        if (shop == null) {
            return Result.fail("店铺不存在！");
        }
        //7.返回
        return Result.ok(shop);
    }

//    private boolean tryLock(String key) {
//        Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(key, "1", LOCK_SHOP_TTL, TimeUnit.SECONDS);
//        return BooleanUtil.isTrue(flag);
//    }
//
//    private void unlock(String key) {
//        stringRedisTemplate.delete(key);
//    }

    @Override
    @Transactional
    public Result update(Shop shop) {
//        private Long id;
        Long id = shop.getId();
        if (id == null) {
            return Result.fail("店铺id不能为空");
        }
        //1.更新数据库
        updateById(shop);
        //2.删除缓存
        stringRedisTemplate.delete(CACHE_SHOP_KEY + id);
        return Result.ok();
    }

    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        //1.判断是否需要根据坐标查询
        if(x==null || y==null){
            //不需要查询坐标，按数据库查
            Page<Shop> page = query()
                    .eq("type_id",typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
            return Result.ok(page.getRecords());
        }
        //2.计算分页参数
        int from = (current - 1)*SystemConstants.DEFAULT_PAGE_SIZE;
        int end = current*SystemConstants.DEFAULT_PAGE_SIZE;
        //3.查询redis，按照距离排序、分页。结果：shopId,distance
        String key = SHOP_GEO_KEY+typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo()
                .search(
                        key,
                        GeoReference.fromCoordinate(x, y),
                        new Distance(5000),
                        RedisGeoCommands.GeoSearchCommandArgs.newGeoSearchArgs().includeDistance().limit(end)
                );
        //4.解析出id
        if(results==null){
            return Result.ok(Collections.emptyList());
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> list = results.getContent();
        //4.1.截取from-end的部分
        List<Long> ids = new ArrayList<>(list.size());
        Map<String,Distance> distanceMap = new HashMap<>(list.size());
        if(list.size()<=from){
            return Result.ok(Collections.emptyList());
        }
        list.stream().skip(from).forEach(result->{ //跳过可能把所有数据跳过了
            //4.2.获取店铺id
            String shopIdStr = result.getContent().getName();
            ids.add(Long.valueOf(shopIdStr));
            //4.3.获取距离
            Distance distance = result.getDistance();
            distanceMap.put(shopIdStr,distance);
        });
        //5.根据id查询shop
        String idStr = StrUtil.join(",", ids);
        List<Shop> shops = query().in("id", ids).last("ORDER BY FIELD ( id," + idStr + ")").list();
        for(Shop shop : shops){
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        }
        //6、返回
        return Result.ok(shops);
    }

//    //缓存穿透--缓存空对象
//    public Shop queryWithPassThrough(Long id) {
//        //1.从redistribution查询商铺缓存
//        String shopJson = stringRedisTemplate.opsForValue().get(CACHE_SHOP_KEY + id);
//        //2.判断是否存在
//        if (StrUtil.isNotBlank(shopJson)) {
//            //3.存在，直接返回
//            Shop shop = JSONUtil.toBean(shopJson, Shop.class);
//            return shop;
//        }
//        //判断命中的是否是空值
//        // (null就是内存中根本没有这个东西，空字符串就是内存中有，但是值是空)
//        //  null是没有数据，而我们存入的空值""
//        if (shopJson != null) {
//            //返回一个错误信息
//            return null;
//        }
//        //4.不存在，根据id查询数据库
//        Shop shop = getById(id);
//        //5.不存在，返回错误
//        if (shop == null) {
//            //将空值写入redis--CACHE_NULL_TTL
//            stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id, "", (long) (Math.random() * 10 + 1), TimeUnit.MINUTES);
//            return null;
//        }
//        //6.存在，写入redis
//        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id, JSONUtil.toJsonStr(shop), CACHE_SHOP_TTL, TimeUnit.MINUTES);
//        //7.返回
//        return shop;
//    }

//    //缓存击穿--互斥锁方式
//    public Shop queryWithMutex(Long id) {
//        //1.从redistribution查询商铺缓存
//        String shopJson = stringRedisTemplate.opsForValue().get(CACHE_SHOP_KEY + id);
//        //2.判断是否存在
//        if (StrUtil.isNotBlank(shopJson)) {
//            //3.存在，直接返回
//            Shop shop = JSONUtil.toBean(shopJson, Shop.class);
//            return shop;
//        }
//        //判断命中的是否是空值
//        // (null就是内存中根本没有这个东西，空字符串就是内存中有，但是值是空)
//        //  null是没有数据，而我们存入的空值""
//        if (shopJson != null) {
//            //返回一个错误信息
//            return null;
//        }
//        //4.实现缓存重建
//        //4.1获取互斥锁
//        String lockKey = "lock:shop:" + id;
//        Shop shop = null;
//        try {
//            boolean isLock = tryLock(lockKey);
//            //4.2判断是否获取成功
//            if (!isLock) {
//                //4.3失败，失眠并重试
//                Thread.sleep(50);
//                return queryWithMutex(id);
//            }
//            //4.3成功，根据id查询数据库
//            shop = getById(id);
//            //模拟重建的延时
//            Thread.sleep(200);
//            //5.不存在，返回错误
//            if (shop == null) {
//                //将空值写入redis--CACHE_NULL_TTL
//                stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id, "", (long) (Math.random() * 10 + 1), TimeUnit.MINUTES);
//                return null;
//            }
//            //6.存在，写入redis
//            stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id, JSONUtil.toJsonStr(shop), CACHE_SHOP_TTL, TimeUnit.MINUTES);
//        } catch (InterruptedException e) {
//            throw new RuntimeException(e);
//        } finally {
//            unlock(lockKey);
//        }
//        //8.返回
//        return shop;
//    }
}
